1. Field of the Invention
The present invention relates to weft thread magazines for laying of weft threads in a warp knitting machine having a pair of parallel, separated, transfer chains and having a carriage reciprocatable between said chains. The carriage comprises at least one group of thread guides which can be operated to transfer the threads to holding devices on the transfer chains.
2. Discussion of the Relevant Art
In a known weft thread magazine of this type, as disclosed in U.S. Pat. No. 3,665,732, a group of thread guides which in practice comprise 12, 18 or 24 single thread guides, are attached to a carriage moving to and fro in a crosswise direction. When the thread guides are connected to the carriage, the weft threads are laid in a diagonal direction whereby the angle of the diagonal is established by the relative motion of the thread guide group. When the thread guide group is firmly attached to a sled which is movable to and fro in the longitudinal direction on the carriage, it is possible to lay the weft threads parallel to each other. It is further possible to provide two or more weft thread groups on the carriage which can lay weft threads sequentially around the same holding means of the transfer chains whereby one group of thread guides lays parallel weft threads and the other thread guides lay diagonal weft threads.
In all of these cases, the patterning possibilities are rather limited, since the pattern repeat is predetermined by the number of thread guides in a group.
A further weft thread magazine for warp knitting machines is known (DEOS No. 2401050). In this arrangement, one out of a group of different weft threads can be fed to a corresponding one of the thread guides. To this end, several sets of weft thread spools are provided for each of the thread guides and a weft thread selector and thread splicer is used to vary the weft threads. In this way, the type of material or the color of the weft thread can be altered. This expansion of patterning variety, however, brings about a lowering of the working speed. Furthermore, care must be taken that the knots are kept outside of the weft inlay segment. Furthermore, the utilization of weft threads having different properties with respect to thread volume, elasticity and the like is very difficult to implement. Additionally, substantial tension peaks occur in the threads when the knots run through the thread guide.
Accordingly, there is a need for a weft thread magazine of the known type but having an expanded possibility of new patterns and, in particular, the possibility of substantially increased pattern types.